Study on Preparation of Sn–Er–Beta Zeolite and Its Catalysis of Glucose to Lactic Acid

A porous Sn–Er–Beta zeolite catalyst was rapidly prepared by introducing Sn source with water bath method and Er source with solid-state ion exchange method. When adding 180 mg catalyst, 225 mg glucose and 10 mL water into a reaction kettle at 200 °C for 2 h, the yield of lactic acid can reach 71.2%. After being recycled 5 times, the lactic acid yield of the catalyst can still reach 45.3%. The physical and chemical properties of Sn–Er–Beta zeolite were characterized, and it was confirmed that the catalyst had a multi-stage pore structure, with Sn and Er elements existing in the zeolite skeleton. Among them, the increase of Lewis acidity, Brønsted acidity and special strong alkaline sites of Sn–Er–Beta zeolite caused by the introduction of Sn, and the Lewis acidic sites are further increased after the introduction of Er. The combination of Sn and Er obviously improves the catalyst’s capability to catalyze glucose and fructose to produce lactic acid. This provides an important reference value for the directional catalytic process of sugars.